During semiconductor wafer fabrication, a lithographic process is typically utilized to transfer a pattern from a mask to the semiconductor wafer. As pattern size continues to decrease in advanced wafer fabrication processes, it becomes more difficult to print a high-contrast image on the semiconductor wafer during lithographic processing. One method of increasing the contrast of the image projected on the wafer utilizes polarized light for illumination in the lithographic process. Polarized light can be provided by utilizing an optical polarizer to polarize incident light that is in an unpolarized, i.e. a randomly polarized, state.
An optical polarizer can provide polarized light by blocking either the transverse electric (TE) or transverse magnetic (TM) component of unpolarized light and allowing the unblocked component to pass through the polarizer. Ideally, the polarized light that is obtained by passing unpolarized through the optical polarizer should include only the unblocked component of the unpolarized light. However, conventional optical polarizers can allow an undesirable percentage of the blocked component of incident unpolarized light to pass through the polarizer, which decreases the quality of the polarized light provided by the polarizer.